CN105427624B - The computational methods and device of a kind of free stream velocity - Google Patents

The computational methods and device of a kind of free stream velocity Download PDF

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CN105427624B
CN105427624B CN201510868762.8A CN201510868762A CN105427624B CN 105427624 B CN105427624 B CN 105427624B CN 201510868762 A CN201510868762 A CN 201510868762A CN 105427624 B CN105427624 B CN 105427624B
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speed
average speed
period
subranges
average
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CN105427624A (en
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何伟魏
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Zhejiang Uniview Technologies Co Ltd
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Zhejiang Uniview Technologies Co Ltd
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G08G1/052—Detecting movement of traffic to be counted or controlled with provision for determining speed or overspeed

Abstract

The present invention provides a kind of computational methods and device of free stream velocity, and this method includes：For each first period in continuous N number of first period, obtain the first historical data that the first headend equipment collects in the first period and the second historical data that the second headend equipment collects in the first period, using the first historical data and the second historical data, it is determined that by the first average speed of each vehicle for monitoring section within the first period；The first average speed positioned at specific speed section is filtered out from the first average speed of each vehicle, the second average speed of the first period is calculated using the first average speed positioned at specific speed section；Using the second average speed corresponding to difference of N number of first period, the 3rd average speed corresponding to the second period is calculated, utilizes the 3rd average speed corresponding to the second period to calculate free stream velocity.By technical scheme, more reasonably free stream velocity is calculated so that the TPI of calculating is consistent with actual road conditions.

Description

The computational methods and device of a kind of free stream velocity
Technical field
The present invention relates to the computational methods and device in monitoring technology field, more particularly to a kind of free stream velocity.
Background technology
With the increase of automobile quantity, the increasing pressure is brought to urban road, road congestion situation is more and more. In order to be preferably that vehicle traveling guides, mitigate road pressure, improve road fluency, reduce the time overhead of driver, lead to Often carry out concentrated expression road grid traffic congestion shape using TPI (Traffic Performance Index, road traffic operation index) Condition, TPI value is 0-10, and 0-2 represents that road network is in unimpeded state, and 3-4 represents that road network is in substantially unimpeded state, 5-6 tables Show that road network is in slight congestion status, 7-8 represents that road network is in moderate congestion status, and 9-10 represents that road network is in heavy congestion shape State.
At present, TPI is determined by average speed of operation and free stream velocity, such as TPI=(1-V/Vf) × 10.V is section Average speed of operation, can be obtained in real time.Vf is the free stream velocity in section, and free stream velocity refers to not influenceed by upstream and downstream condition In the case of, the free travel speed of vehicle when section is unimpeded, in such a situa-tion, the free travel speed of vehicle is generally near The speed limit upper limit in section, therefore, the free stream velocity using the speed limit upper limit in section as the section.TPI runs for road traffic Index.
In urban road, section can be influenceed by various factors such as traffic control, traffic lights, pedestrians, therefore vehicle Free travel speed is not up to the speed limit upper limit in section, i.e. the free stream velocity in the section is unable to reach in the speed limit in the section Limit.Obviously the selection of free stream velocity can be caused to be inaccurate, then directly as free stream velocity the speed limit upper limit in section The TPI for causing to calculate is not consistent with actual road conditions.
The content of the invention
The present invention provides a kind of computational methods of free stream velocity, and for monitoring section, the first headend equipment is used to gather Car data is crossed in the porch in the monitoring section, and car is crossed in the exit that the second headend equipment is used to gather the monitoring section Data, it the described method comprises the following steps：
For each first period in continuous N number of first period, first headend equipment is obtained at described first The second historical data that the first historical data and second headend equipment that section collects collect in first period, and Using first historical data and second historical data, it is determined that by the monitoring section within first period First average speed of each vehicle；Filtered out from the first average speed of each vehicle positioned at specific speed section First average speed, and utilize the second average speed of the first average speed calculating first period positioned at specific speed section Degree；
Using the second average speed corresponding to N number of first period difference, the 3rd is average corresponding to the second period of calculating Speed, and calculate free stream velocity using the 3rd average speed corresponding to second period.
It is described to utilize first historical data and second historical data, it is determined that passing through institute within first period The process of the first average speed of each vehicle in monitoring section is stated, is specifically included：For passing through institute within first period Each vehicle in monitoring section is stated, determines that the vehicle enters the monitoring road using the first historical data corresponding to the vehicle The very first time of section, and determine that the vehicle leaves the of the monitoring section using the second historical data corresponding to the vehicle Two times；Running time of the vehicle in the monitoring section is determined using the very first time and second time, and Utilize the first average speed of vehicle described in the length computation in the running time and the monitoring section；
The first average speed positioned at specific speed section is filtered out in first average speed from each vehicle Process, specifically include：First speed restrictive block and the second speed restrictive block in the monitoring section are obtained, and takes the first speed limit area Between and the common factor of second speed restrictive block be the specific speed section；For passing through the monitoring within first period Each vehicle in section, when the first average speed of the vehicle is located at the specific speed section, retain the vehicle First average speed；When the first average speed of the vehicle is not located at the specific speed section, the vehicle is deleted First average speed；Wherein, first speed restrictive block is from VminTo Vmax, second speed restrictive block is from 0.6VmaxArrive Vmax, VminBe it is described monitoring section minimum speed limit, VmaxIt is the maximum speed limit in the monitoring section.
First average speed using positioned at specific speed section calculates the second average speed of first period Process, specifically include：By the specific speed interval division into k speed subranges, for positioned at the every of specific speed section Individual first average speed finds corresponding speed subranges, counts the first average speed quantity corresponding to each speed subranges, And obtain corresponding relation of each speed subranges with corresponding first average speed quantity；For each speed subranges, profit Corresponding relation with the speed subranges with corresponding first average speed quantity, weight ginseng is distributed for the speed subranges Number, and using all first average speeds corresponding to the speed subranges, calculate Siping City corresponding to the speed subranges Equal speed；It is average using weight parameter corresponding to each speed subranges difference in the k speed subranges and the 4th Speed, calculate the second average speed of first period.
For each speed subranges in the k speed subranges, it is described using the speed subranges with it is corresponding The first average speed quantity corresponding relation, for the speed subranges distribute weight parameter process, specifically include：According to Order from low speed subinterval to high speed subinterval, the k speed subranges are ranked up；Determine i-th of speed sub-district Between the first sub- weight parameter q1 be (2*i)/[(1+k) * k], and the first average speed quantity according to corresponding to speed subranges, The the second sub- weight parameter q2 for determining i-th of speed subranges isWherein, i value is 1, 2 ..., k, niFor the first average speed quantity, n corresponding to i-th of speed subrangesjFor first corresponding to j-th of speed subranges Average speed quantity；The first sub- weight parameter in high speed subinterval is more than the first sub- weight parameter in low speed subinterval, and first is flat The second small sub- weight parameter of equal number of speed amount is more than the second big sub- weight parameter of the first average speed quantity；Calculate all speed Spend weight ratio λ corresponding to the first sub- weight parameter in subinterval1And the second sub- weight parameter pair of all speed subranges The weight ratio λ answered2, and the weight parameter for calculating i-th of speed subranges is specially：(the of i-th of speed subranges Weight ratio λ described in one sub- weight parameter *1Weight ratio λ described in the second sub- weight parameter * of i-th of speed subranges of)+(2)。
Second average speed corresponding to utilization N number of first period difference, is calculated the 3rd corresponding to the second period The process of average speed, is specifically included：3rd average speed corresponding to calculating second period isIts In, the value of the i is 1,2 ..., N, the niFor the first average speed quantity filtered out corresponding to i-th of first periods, The n is all the first average speed quantity filtered out, the V corresponding to N number of first periodiFor i-th of first periods pair The second average speed answered；
The process that free stream velocity is calculated using the 3rd average speed corresponding to the second period, is specifically included：By institute The 3rd average speed corresponding to the second period is stated as free stream velocity；Or using the 3rd corresponding to the second period of continuous N Average speed calculates free stream velocity；Free stream velocity is calculated using the 3rd average speed corresponding to the second period of continuous N Process, specifically include：Calculating free stream velocity isWherein, the value of the j is 1,2 ..., and M is described mjFor the first average speed quantity filtered out corresponding to j-th of second periods, the m is to own corresponding to M the second periods The the first average speed quantity filtered out, the VjFor the 3rd average speed corresponding to j-th of second periods.
The present invention provides a kind of computing device of free stream velocity, and for monitoring section, the first headend equipment is used to gather Car data is crossed in the porch in the monitoring section, and car is crossed in the exit that the second headend equipment is used to gather the monitoring section Data, the computing device of the free stream velocity specifically include：
Determining module, for for each first period in continuous N number of first period, obtaining first headend equipment The first historical data and second headend equipment collected in first period collected in first period Two historical datas, using first historical data and second historical data, it is determined that passing through institute within first period State the first average speed of each vehicle in monitoring section；
Screening module, for the first average speed of each vehicle determined for the determining module, from described each The first average speed positioned at specific speed section is filtered out in first average speed of vehicle；
Computing module, for the first average speed positioned at specific speed section filtered out for screening module, utilize The first average speed positioned at specific speed section calculates the second average speed of first period；And using described N number of Second average speed corresponding to first period difference, the 3rd average speed corresponding to the second period is calculated, and utilize described second 3rd average speed corresponding to period calculates free stream velocity.
The determining module, specifically for utilizing first historical data and second historical data, it is determined that During the first average speed for passing through each vehicle in the monitoring section in first period, for described first By each vehicle in the monitoring section in period, determine that the vehicle enters using the first historical data corresponding to the vehicle Enter the very first time in the monitoring section, and it is described using the second historical data corresponding to the vehicle to determine that the vehicle leaves Monitor second time in section；Determine the vehicle in the monitoring section using the very first time and second time Running time, and utilize the first average speed of vehicle described in the length computation in the running time and the monitoring section；
The screening module, specifically for being filtered out in the first average speed from each vehicle positioned at the spy During the first average speed for determining speed interval, the first speed restrictive block and the second speed limit area in the monitoring section are obtained Between, and it is the specific speed section to take the common factor of first speed restrictive block and second speed restrictive block；For institute State by each vehicle in the monitoring section in the first period, when the first average speed of the vehicle is located at the specific speed When spending section, then retain the first average speed of the vehicle；When the first average speed of the vehicle is not positioned at described specific During speed interval, then the first average speed of the vehicle is deleted；Wherein, first speed restrictive block is specifically from VminArrive Vmax, second speed restrictive block is specifically from 0.6VmaxTo Vmax, the VminIt is the minimum speed limit in the monitoring section, it is described VmaxIt is the maximum speed limit in the monitoring section.
The computing module, specifically for calculating described first using the first average speed positioned at specific speed section During the second average speed of period, by the specific speed interval division into k speed subranges, for positioned at specific speed Each first average speed in degree section finds corresponding speed subranges, and it is average to count corresponding to each speed subranges first Speed quantity, and obtain corresponding relation of each speed subranges with corresponding first average speed quantity；For each speed Subinterval, the corresponding relation using the speed subranges with corresponding first average speed quantity, it is the speed subranges Weight parameter is distributed, and using all first average speeds corresponding to the speed subranges, calculates the speed subranges pair The 4th average speed answered；Using in the k speed subranges each speed subranges respectively corresponding to weight parameter with And the 4th average speed, calculate the second average speed of first period.
For each speed subranges in k speed subranges, the computing module, specifically for utilizing the speed Corresponding relation of the subinterval with corresponding first average speed quantity is spent, the process of weight parameter is distributed for the speed subranges In, according to the order from low speed subinterval to high speed subinterval, the k speed subranges are ranked up；Determine i-th of speed The the first sub- weight parameter q1 for spending subinterval is (2*i)/[(1+k) * k], and the first average speed according to corresponding to speed subranges Number of degrees amount, the second sub- weight parameter q2 for determining i-th of speed subranges areWherein, i takes It is worth for 1,2 ..., k, niFor the first average speed quantity, n corresponding to i-th of speed subrangesjIt is corresponding for j-th of speed subranges The first average speed quantity；The first sub- weight parameter in high speed subinterval is more than the first sub- weight parameter in low speed subinterval, The second small sub- weight parameter of first average speed quantity is more than the second big sub- weight parameter of the first average speed quantity；Calculate Weight ratio λ corresponding to first sub- weight parameter of all speed subranges1And the second sub- weight of all speed subranges Weight ratio λ corresponding to parameter2, and the weight parameter for calculating i-th of speed subranges is specially：(i-th of speed sub-district Between the first sub- weight parameter * described in weight ratio λ1Weight described in the second sub- weight parameter * of i-th of speed subranges of)+( Ratio λ2)。
The computing module, specifically for using the second average speed corresponding to difference of N number of first period, calculating second During 3rd average speed corresponding to period, the 3rd average speed corresponding to calculating second period isThe value of the i is 1,2 ..., N, the niIt is first flat for what is filtered out corresponding to i-th of first periods Equal number of speed amount, the n is all the first average speed quantity filtered out, the V corresponding to N number of first periodiFor i-th Second average speed corresponding to first period；
The computing module, specifically for calculating free stream velocity using the 3rd average speed corresponding to the second period During, using the 3rd average speed corresponding to second period as free stream velocity；Or during using continuous N second The 3rd average speed calculates free stream velocity corresponding to section；Utilizing the 3rd average speed meter corresponding to the second period of continuous N During calculating free stream velocity, calculating free stream velocity isThe value of the j is 1,2 ..., M, institute State mjFor the first average speed quantity filtered out corresponding to j-th of second periods, the m is institute corresponding to M the second periods There are the first average speed quantity filtered out, the VjFor the 3rd average speed corresponding to j-th of second periods.
Based on above-mentioned technical proposal, in the embodiment of the present invention, for monitoring section, the first headend equipment is used for acquisition monitoring Car data is crossed in the porch in section, and the second headend equipment crosses car data for the exit in acquisition monitoring section, for even Continue each first period in N number of first period, obtain the first historical data that the first headend equipment collects in the first period The second historical data collected with the second headend equipment in the first period, it is true using the first historical data and the second historical data First average speed of each vehicle being scheduled in the first period by monitoring section, and from the first average speed of each vehicle In filter out the first average speed positioned at specific speed section, and utilize the first average speed meter positioned at specific speed section The second average speed of the first period is calculated, using the second average speed corresponding to difference of N number of first period, calculated for the second period pair The 3rd average speed answered, and calculate free stream velocity using the 3rd average speed corresponding to the second period.In aforesaid way, Car data is crossed by using what the first headend equipment and the second headend equipment of monitoring section both sides collected, calculates more adduction The free stream velocity of reason, and when calculating TPI using free stream velocity, the TPI that can to calculate is consistent with actual road conditions.
Brief description of the drawings
Fig. 1 is the flow chart of the computational methods of the free stream velocity in one embodiment of the present invention；
Fig. 2 is the hardware structure diagram of the management equipment in one embodiment of the present invention；
Fig. 3 is the structure chart of the computing device of the free stream velocity in one embodiment of the present invention.
Embodiment
Purpose in term used in this application merely for the sake of description specific embodiment, and unrestricted the application.This Shen Please " one kind " with the singulative used in claims, " described " and "the" are also intended to including most forms, unless Context clearly shows that other implications.It is also understood that term "and/or" used herein refers to comprising one or more Associated list items purpose any or all may combine.
It will be appreciated that though various information, but this may be described using term first, second, third, etc. in the application A little information should not necessarily be limited by these terms.These terms are only used for same type of information being distinguished from each other out.For example, do not departing from In the case of the application scope, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as One information.Depending on linguistic context, in addition, used word " if " can be construed to " ... when " or " when ... " Or " in response to determining ".
For problems of the prior art, a kind of computational methods of free stream velocity are proposed in the embodiment of the present invention, This method can be applied in the management equipment for calculating free stream velocity, and the management equipment can obtain from monitoring system Correlation crosses car data.Wherein, free stream velocity refers in the case of not influenceed by upstream and downstream condition, car when monitoring section is unimpeded Free travel speed.In addition, in monitoring system, each headend equipment (such as web camera, analog video camera, encoder) For gathering car data, license plate number information, temporal information when passing through such as vehicle, can be identified together based on license plate number information One car, vehicle elapsed time can be identified based on temporal information.For monitoring section, it is assumed that the first headend equipment is used for The car data of crossing of the porch in the monitoring section is gathered, car is crossed in the exit that the second headend equipment is used to gather the monitoring section Data.For example, monitoring section is that the first headend equipment is deployed in position A from position A (porch) to position B (exit), and For gathering the car data of crossing from the position A vehicles passed through, the second headend equipment is deployed in position B, and for gathering from position B The vehicle of process crosses car data.Under above-mentioned application scenarios, as shown in figure 1, the computational methods of the free stream velocity specifically may be used To comprise the following steps：
Step 101, for the monitoring section, for each first period in continuous N number of first period, before obtaining first The first historical data and the second headend equipment that end equipment collects in first period collected in first period second Historical data, and using first historical data and second historical data, it is determined that passing through the monitoring road within first period First average speed of each vehicle of section；Filtered out from the first average speed of each vehicle positioned at specific speed section First average speed, and first average speed of the utilization positioned at specific speed section calculates the second average speed of first period Degree.
Wherein, monitoring section refers to need the section for calculating free stream velocity, has the first headend equipment to be used to gather the prison Control the porch in section crosses car data, and have exit of second headend equipment for gathering the monitoring section crosses car data, First headend equipment and the second headend equipment are the headend equipments of bayonet system.
Wherein, the duration of the first period can be configured according to actual conditions, such as 20 minutes.In one example, The duration of first period needs to be more than the time required for vehicle reaches the exit in monitoring section from the porch in monitoring section, That is vehicle can exercise the exit to monitoring section in the duration of the first period from the porch in monitoring section.Moreover, In the duration of first period, can cause through monitoring section vehicle it is as more as possible, furthermore, it is possible to so that the first period when Length is as small as possible.
Wherein, N value is relevant with the duration of the first period, it is assumed that the first period when a length of 20 minutes, then have within 1 day Continuous 72 the first periods, therefore, N can be 72, i.e., for each first period in continuous 72 the first periods, hold Row step 101, this continuous 72 first period can be followed successively by 0:00-0:20,0:20-0:40,0:40-1:00,1:00-1: 20 ..., 23:40-0:00.In order to facilitate description, subsequently (it is assumed to be 8 with first period:00-8:20) step described 101。
For first period in continuous N number of first period, step 101 specifically includes following steps：
Step 1, obtain the first historical data (cross car data) that the first headend equipment collects in first period and the The second historical data (crossing car data) that two headend equipments collect in first period.
Wherein, the car data excessively collected due to each headend equipment can be stored in monitoring system, and what is stored crosses car data It is referred to as the historical data of monitoring system.Therefore, for monitoring the first headend equipment and the outlet that the porch in section is disposed Locate the second headend equipment of deployment, can get that the first headend equipment collects in first period from monitoring system the The second historical data that one historical data and the second headend equipment collect in first period, specific acquisition process is herein Repeat no more.
Step 2, using the first historical data of first period and the second historical data of first period, it is determined that Pass through the first average speed of each vehicle in the monitoring section in first period.
In the embodiment of the present invention, using the first historical data of the first period and the second historical data of the first period, It is determined that within first period by the monitoring section each vehicle the first average speed process, can specifically include but It is not limited to following manner：Each vehicle for passing through the monitoring section within first period, utilizes corresponding to the vehicle the One historical data determines that the vehicle enters the very first time in the monitoring section, and true using the second historical data corresponding to the vehicle The fixed vehicle leaves second time in the monitoring section；Determine the vehicle in the monitoring using the very first time and second time The running time in section, and utilize the first average speed of the running time and the length computation in the monitoring section vehicle.
Wherein, refer within the first period by the vehicle in monitoring section, within the first period, vehicle is from monitoring section Porch is driven into and (known by the first historical data), now can determine the car using the first historical data corresponding to the vehicle The very first time in the entrance monitoring section.Moreover, within the first period, the vehicle rolls away from (logical from the exit in monitoring section The second historical data is crossed to know), now it can determine that the vehicle leaves the monitoring using the second historical data corresponding to the vehicle Second time in section.
In one example, multiple headend equipments may be disposed by monitoring on each position in section, some headend equipments The porch in monitoring section is deployed in, some headend equipments are deployed in the exit in monitoring section, and some headend equipments are deployed in Monitor the other positions in section.Based on this, by the latitude and longitude information of each headend equipment each headend equipment can be judged in the prison The position in section is controlled, then determines to be deployed in the first headend equipment of the porch in monitoring section and is deployed in monitoring section Exit the second headend equipment.
For each vehicle, judge the vehicle whether be vehicle in the first period by the monitoring section mode Can be：That the vehicle is read from each headend equipment in monitoring section crosses car record；If there was only a mistake within the first period Car records, then it represents that the vehicle does not roll the monitoring section away from also, and the vehicle is not to pass through the monitoring section in the first period Vehicle.Car record is crossed more than or equal to two if having within the first period, if do not wrapped in capturing the headend equipment of the vehicle Second headend equipment of the first headend equipment and/or exit containing porch, then the vehicle is not by being somebody's turn to do in the first period Monitor the vehicle in section；If capture the headend equipment of the vehicle while the first headend equipment comprising porch and exit The second headend equipment, then the vehicle is by the vehicle in the monitoring section in the first period.
Vehicle for passing through the monitoring section within the first period, the very first time corresponding to the vehicle and the can be utilized Two times determined running time of the vehicle in the monitoring section, and the first average speed for calculating the vehicle is the monitoring section Length divided by the running time.Wherein it is possible to the information such as geometry and longitude and latitude based on monitoring section calculates this The length in section is monitored, concrete mode repeats no more.
Step 3, filter out from the first average speed of each vehicle the first average speed positioned at specific speed section. Wherein, the first average speed filtered out refers to effective first average speed.
In the embodiment of the present invention, first positioned at specific speed section is filtered out from the first average speed of each vehicle The process of average speed, it can specifically include but is not limited to following manner：Obtain first speed restrictive block and in the monitoring section Two speed restrictive blocks, and it is specific speed section to take the common factor of first speed restrictive block and second speed restrictive block；For first By each vehicle in the monitoring section in period, when the first average speed of the vehicle is located at specific speed section, then protect Stay the first average speed of the vehicle；When the first average speed of the vehicle is not located at specific speed section, then the car is deleted The first average speed；Wherein, first speed restrictive block is from VminTo Vmax, second speed restrictive block is from 0.6VmaxArrive Vmax, VminIt is the minimum speed limit in the monitoring section, VmaxIt is the maximum speed limit in the monitoring section.
When calculating the first average speed of vehicle based on historical data, different grades of first average speed letter is had Breath is first flat when the first mean velocity information when the first mean velocity information when such as exceeding the speed limit, road congestion, normally travel Equal velocity information etc..In these first mean velocity informations, the mean velocity information of part first can not use, such as road congestion When the first mean velocity information, its first average speed very little, freedom can be significantly dragged down using these first average speeds Flow velocity degree, the first mean velocity information when and for example exceeding the speed limit, its first average speed is very big, uses these the first average speed meetings Significantly draw high free stream velocity.Based on this, it is necessary to be screened to the first average speed, and specific speed section is a use It is just effective only when the first average speed of vehicle is located at the specific speed section in the section for screening the first average speed, Can just first average speed be used to calculate free stream velocity.
Definition in view of free stream velocity refers in the case of not influenceed by upstream and downstream condition, when monitoring section is unimpeded The free travel speed of vehicle, and in actual monitored section, although being influenceed by various external factor so that the traveling speed of vehicle Degree is difficult to reach theoretical free stream velocity, still, should also be as close as free flow velocity when calculating free stream velocity The theoretical value of degree.Based on this, specific speed section needs the speed limit requirement for meeting monitoring section, and the speed limit requirement for monitoring section can To be from VminTo Vmax, VminIt is the minimum speed limit in the monitoring section, VmaxIt is the maximum speed limit in the monitoring section.In addition, it is based on Monitor the maximum speed limit V in sectionmax, then the travel speed typically 0.8V of unobstructed condition is metmaxTo Vmax, and consider Maximum speed limit can usually draw high TPI values, therefore substantially unimpeded travel speed is also counted, therefore, specific speed section 0.6V can be metmaxTo VmaxSpeed limit requirement.Based on the requirement of above-mentioned two speed limit, the common factor that the two speed limits can be taken to require As specific speed section.
Wherein, the speed limit for monitoring section requires relevant with the grade for monitoring section, and urban road can be divided into following grade： Through street, major trunk roads, subsidiary road, branch road, the speed limit of different brackets road require different.
Step 4, the second average speed for calculating using the first average speed positioned at specific speed section first period, The first follow-up average speed each means the first average speed positioned at specific speed section.
It is flat using second of the first average speed the first period of calculating positioned at specific speed section in the embodiment of the present invention The process of equal speed, can specifically include but is not limited to following manner：By specific speed interval division into k speed subranges, Corresponding speed subranges are found for each first average speed positioned at specific speed section, count each speed subranges pair The the first average speed quantity answered, and obtain corresponding relation of each speed subranges with corresponding first average speed quantity. For each speed subranges, the corresponding relation using the speed subranges with corresponding first average speed quantity, for the speed Subinterval distribution weight parameter is spent, and using all first average speeds corresponding to the speed subranges, calculates the speed sub-district Between corresponding to the 4th average speed；Using in k speed subranges each speed subranges respectively corresponding to weight parameter with And the 4th average speed, calculate the second average speed of the first period.
For example, it is assumed that specific speed section is [50,80], then by specific speed interval division into speed subranges 1 [50, 60), speed subranges 2 [60,70), 3 speed subranges such as speed subranges 3 [70,80].The first of speed subranges 1 is flat Equal speed includes 50,52,54,56,58, and the first average speed of speed subranges 2 includes 60,62,64,66, speed subranges 3 The first average speed include 70,72,74.First average speed quantity corresponding to speed subranges 1 is 5, and speed subranges 2 are right The the first average speed quantity answered is 4, and the first average speed quantity corresponding to speed subranges 3 is 3.
For each speed subranges, closed using speed subranges are corresponding with corresponding first average speed quantity System, during distributing weight parameter for the speed subranges, it is contemplated that the definition of free stream velocity, can be that speed is higher Higher weight parameter is distributed in high speed subinterval, can be that the small speed subranges of the first average speed quantity distribute higher power Weight parameter, the i.e. weight parameter in high speed subinterval are more than the weight parameter in low speed subinterval, the small speed of the first average speed quantity The weight parameter for spending subinterval is more than the weight parameter of the big speed subranges of the first average speed quantity.Based on this, can make The free stream velocity calculated is in the case of not influenceed by upstream and downstream condition, and vehicle when monitoring section is unimpeded freely travels Speed.
Under above-mentioned application scenarios, because the speed of speed subranges 1 is minimum, and the first average speed quantity is maximum, speed The speed highest in subinterval 3 is spent, and the first average speed quantity is minimum, therefore, the weight parameter meeting distributed for speed subranges 3 More than the weight parameter distributed for speed subranges 2, moreover, it is speed that can be more than for the weight parameter that speed subranges 2 distribute The weight parameter that subinterval 1 is distributed.
Under above-mentioned application scenarios, for speed subranges 1, the corresponding to speed subranges 1 all first average speed are utilized Spend (50,52,54,56,58), the 4th average speed corresponding to calculating speed subinterval 1 is 54.For speed subranges 2, utilize All first average speeds (60,62,64,66) corresponding to speed subranges 2, the 4th is average corresponding to calculating speed subinterval 2 Speed is 63.For speed subranges 3, using all first average speeds (70,72,74) corresponding to speed subranges 3, calculate 4th average speed corresponding to speed subranges 3 is 72.Further, the second average speed of the first period of calculating isWherein, k be speed subranges quantity, QiFor weight parameter, V corresponding to i-th of speed subrangesiFor i-th 4th average speed corresponding to speed subranges.Based on this, the second average speed that can calculate for the first period is specially：(speed Spend the weight parameter * 54 in subinterval 1)+(the weight parameter * 63 of speed subranges 2)+(weight parameter * of speed subranges 3 72)。
Wherein, it is contemplated that for speed subranges distribution weight parameter is relevant with the speed of speed subranges and and speed The first average speed quantity in subinterval is relevant, therefore, is utilizing speed subranges and corresponding first average speed quantity Corresponding relation, during distributing weight parameter for speed subranges, two factors can be based respectively on as speed subranges point The speed is obtained with the first sub- weight parameter and the second sub- weight parameter, and using the first sub- weight parameter and the second sub- weight parameter Spend the weight parameter in subinterval.
In the embodiment of the present invention, for each speed subranges in k speed subranges, using the speed subranges with The corresponding relation of corresponding first average speed quantity, the process of weight parameter is distributed for the speed subranges, can specifically be wrapped Include but be not limited to following manner：According to the order from low speed subinterval to high speed subinterval, k speed subranges are arranged Sequence；The the first sub- weight parameter q1 for determining i-th of speed subranges is (2*i)/[(1+k) * k], corresponding according to speed subranges The first average speed quantity, the second sub- weight parameter q2 for determining i-th of speed subranges is I value is 1,2 ..., k, niFor the first average speed quantity, n corresponding to i-th of speed subrangesjFor j-th of speed sub-district Between corresponding to the first average speed quantity；The first sub- weight parameter in high speed subinterval is more than the first sub- weight in low speed subinterval Parameter, the second small sub- weight parameter of the first average speed quantity are more than the second big sub- weight ginseng of the first average speed quantity Number.Calculate weight ratio λ corresponding to the first sub- weight parameter of all speed subranges1And the second of all speed subranges Weight ratio λ corresponding to sub- weight parameter2, and the weight parameter for calculating i-th of speed subranges is：(i-th of speed subranges First sub- weight parameter * weight ratios λ1Second sub- weight parameter * weight ratios λ of i-th of speed subranges of)+(2)。
Wherein, weight ratio λ corresponding to the first of each speed subranges the sub- weight parameter1All same, and each speed Weight ratio λ corresponding to the second sub- weight parameter in subinterval2All same.
Wherein, according to the order from low speed subinterval to high speed subinterval, the result that k speed subranges are ranked up For speed subranges 1, speed subranges 2 and speed subranges 3, the first sub- weight parameter q1 of the 1st speed subranges is determined For (2*1)/[(1+3) * 3]=1/6, the first sub- weight parameter q1 for determining the 2nd speed subranges is (2*2)/[(1+3) * 3] =1/3, the first sub- weight parameter q1 for determining the 3rd speed subranges is (2*3)/[(1+3) * 3]=1/2.Due to speed The first average speed quantity in section 1 is 5, and the first average speed quantity of speed subranges 2 is 4, the first of speed subranges 3 Average speed quantity be 3, accordingly, it is determined that the second sub- weight parameter q2 of the 1st speed subranges be (1-5/12)/(3-1)= 7/24, the second sub- weight parameter q2 for determining the 2nd speed subranges is (1-4/12)/(3-1)=8/24, determines the 3rd speed The the second sub- weight parameter q2 for spending subinterval is (1-3/12)/(3-1)=9/24.
Based on above-mentioned processing, the tables of data shown in table 1 can be obtained.It is averaged based on the 4th average speed in table 1, first The information such as speed quantity, the first sub- weight parameter and the second sub- weight parameter, analytic hierarchy process (AHP) can be utilized, calculates all speed Spend weight ratio λ corresponding to the first sub- weight parameter in subinterval1, all speed subranges the second sub- weight parameter corresponding to Weight ratio λ2, and the weight parameter Q of i-th of speed subranges can be calculatediFor：(the first son of i-th of speed subranges Weight parameter * weight ratios λ1The second sub- weight parameter * weight ratios λ of i-th of speed subranges of)+(2).In this manner it is possible to Respectively obtain the weight parameter of speed subranges 1, the weight parameter of speed subranges 2, the weight parameter of speed subranges 3.When So, in actual applications, the weight ratio λ of all speed subranges can also be directly configured according to practical experience1, weight ratio λ2Numerical value, this mode no longer repeats in detail herein.
Table 1
Speed subranges identify 1 2 3
4th average speed 54 63 72
First average speed quantity 5 4 3
First sub- weight parameter 1/6 2/6 3/6
Second sub- weight parameter 7/24 8/24 9/24
Step 102, using the second average speed corresponding to difference of N number of first period, calculate the 3rd corresponding to the second period Average speed, and calculate free stream velocity using the 3rd average speed corresponding to the second period.
In the embodiment of the present invention, using the second average speed corresponding to difference of N number of first period, it is corresponding to calculate for the second period The 3rd average speed process, can specifically include but is not limited to：Calculating the 3rd average speed corresponding to the second period isWherein, i value is 1,2 ..., N, niFirst to be filtered out corresponding to i-th of first periods is averaged Speed quantity, n are all the first average speed quantity filtered out, V corresponding to N number of first periodiFor i-th of first periods pair The second average speed answered.
Wherein, after step 101 is performed for each first period, it is (corresponding that continuous 72 the first periods can be obtained In 1 day) in each first period the second average speed and the first average speed quantity, first period as corresponding to table 1 The first average speed quantity be 12.On this basis, the second average speed corresponding to 72 the first periods difference can be utilized And the first average speed quantity, calculate the 3rd average speed for one day, referred to as per day speed.Specifically calculating During, it is contemplated that this factor of vehicle flowrate, when can be the first of vehicle flowrate more (i.e. the first average speed quantity is larger) Section distributes less weight parameter, it is consequently possible to calculate going out the 3rd average speed and beingWherein, N first The quantity 72 of period, i value can be 1,2 ..., 72, niFor the first average speed quantity, n corresponding to i-th of first periods For all first average speed quantity, i.e. n=n corresponding to 72 the first periods1+n2+..+n72,ViFor i-th of first periods pair The second average speed answered.
In the embodiment of the present invention, the process of free stream velocity, tool are calculated using the 3rd average speed corresponding to the second period Body can include but is not limited to following manner：Directly using the 3rd average speed corresponding to the second period as free stream velocity.Or Person, the 3rd average speed corresponding to the second period of continuous N can be utilized to calculate free stream velocity.Further, utilizing During the 3rd average speed calculates free stream velocity corresponding to second period of continuous N, it can specifically include but is not limited to Following manner：Calculating free stream velocity can beWherein, j value is 1,2 ..., M, mjFor j-th The the first average speed quantity filtered out corresponding to second period, m be corresponding to M the second periods it is all filter out it is first flat Equal number of speed amount, VjFor the 3rd average speed corresponding to j-th of second periods.
Wherein, can be directly by day after per day speed (the 3rd average speed corresponding to the second period) is calculated Average speed is as free stream velocity.Different in view of the vehicle flowrate of not same date, such as workaday vehicle flowrate is more than inoperative The vehicle flowrate of day, therefore the 3rd average speed corresponding to the second period of continuous N can also be utilized to calculate free stream velocity.M's Value can select according to practical experience, and such as M is 15 or 30, so that M is 30 as an example, then be calculated based on the per day speed of 30 days Free stream velocity, i.e. free stream velocity are moon free stream velocity, and final free stream velocity is used as using moon free stream velocity.
Wherein, after above-mentioned processing is performed for continuous 30 the second periods, it is (right that continuous 30 the second periods can be obtained Should be January) in each second period the 3rd average speed and the first average speed quantity (the first i.e. daily average speed Quantity).On this basis, the 3rd average speed and the first average speed number corresponding to 30 the second periods difference can be utilized Amount, calculates monthly average speed, and using monthly average speed as final free stream velocity.In specific calculating process, examine Consider vehicle flowrate this factor, can be vehicle flowrate more (i.e. the first average speed quantity is larger) the second period distribute it is smaller Weight parameter, it is consequently possible to calculate going out free stream velocity (front-month average speed) and beingWherein, M The quantity 30 of two periods, j value is 1,2 ..., 30, mjIt is for the first average speed quantity, m corresponding to j-th of second periods All first average speed quantity, i.e. m=m corresponding to 30 the second periods1+m2+..+m30,VjIt is corresponding for j-th of second periods The 3rd average speed.
Wherein, for monitoring section, after free stream velocity is calculated, TPI can be calculated based on free stream velocity, Such as TPI=(1-V/Vf) × 10.V can be the average speed of operation in the monitoring section, and Vf can be the freedom in the monitoring section Flow velocity degree, TPI are that the road traffic in the monitoring section runs index.TPI is used for concentrated expression road grid traffic congestion, TPI Value be 0-10,0-2 represents that road network be in unimpeded state, and 3-4 represents that road network is in substantially unimpeded state, 5-6 expression road networks In slight congestion status, 7-8 represents that road network is in moderate congestion status, and 9-10 represents that road network is in heavy congestion state.
Based on above-mentioned technical proposal, in the embodiment of the present invention, for monitoring section, the first headend equipment is used for acquisition monitoring Car data is crossed in the porch in section, and the second headend equipment crosses car data for the exit in acquisition monitoring section, for even Continue each first period in N number of first period, obtain the first historical data that the first headend equipment collects in the first period The second historical data collected with the second headend equipment in the first period, it is true using the first historical data and the second historical data First average speed of each vehicle being scheduled in the first period by monitoring section, and from the first average speed of each vehicle In filter out the first average speed positioned at specific speed section, and utilize the first average speed meter positioned at specific speed section The second average speed of the first period is calculated, using the second average speed corresponding to difference of N number of first period, calculated for the second period pair The 3rd average speed answered, and calculate free stream velocity using the 3rd average speed corresponding to the second period.In aforesaid way, Car data is crossed by using what the first headend equipment and the second headend equipment of monitoring section both sides collected, calculates more adduction The free stream velocity of reason, and when calculating TPI using free stream velocity, the TPI that can to calculate is consistent with actual road conditions.
Based on the inventive concept same with the above method, a kind of meter of free stream velocity is additionally provided in the embodiment of the present invention Device is calculated, the computing device of the free stream velocity is applied in management equipment.Wherein, the computing device of the free stream velocity can be with Realized, can also be realized by way of hardware or software and hardware combining by software.Exemplified by implemented in software, patrolled as one Device in volume meaning, it is corresponding calculating in reading non-volatile storage by the processor of the management equipment where it What machine programmed instruction was formed.For hardware view, as shown in Fig. 2 the computing device for free stream velocity proposed by the present invention A kind of hardware structure diagram of the management equipment at place, in addition to the processor shown in Fig. 2, nonvolatile memory, management equipment Other hardware can also be included, be such as responsible for forwarding chip, network interface, the internal memory of processing message；From hardware configuration, The management equipment is also possible to be distributed apparatus, may include multiple interface cards, to carry out Message processing in hardware view Extension.
As shown in figure 3, the structure chart of the computing device for free stream velocity proposed by the present invention, the free stream velocity Computing device is applied in management equipment, and for monitoring section, the first headend equipment is used for the entrance for gathering the monitoring section Car data is crossed at place, and car data, the free flow velocity are crossed in the exit that the second headend equipment is used to gather the monitoring section The computing device of degree specifically includes：
Determining module 11, for for each first period in continuous N number of first period, obtaining the first headend equipment and existing The first historical data and second headend equipment that first period collects collected in first period second Historical data, using first historical data and second historical data, it is determined that by described within first period Monitor the first average speed of each vehicle in section；
Screening module 12, for the first average speed of each vehicle determined for determining module, from each car The first average speed in filter out the first average speed positioned at specific speed section；
Computing module 13, for the first average speed positioned at specific speed section filtered out for screening module, profit The second average speed of first period is calculated with the first average speed positioned at specific speed section；And utilize the N Individual first period respectively corresponding to the second average speed, calculate the 3rd average speed corresponding to the second period, and utilize described the 3rd average speed corresponding to two periods calculates free stream velocity.
The determining module 11, specifically for utilizing first historical data and the second historical data, it is determined that in institute During the first average speed for stating each vehicle in the first period by the monitoring section, at described first By each vehicle in the monitoring section in section, determine that the vehicle enters using the first historical data corresponding to the vehicle The very first time in the monitoring section, and determine that the vehicle leaves the prison using the second historical data corresponding to the vehicle Control second time in section；Row of the vehicle in the monitoring section is determined using the very first time and second time Sail the time, and utilize the first average speed of vehicle described in the length computation in the running time and the monitoring section；
The screening module 12, specifically for being filtered out in the first average speed from each vehicle positioned at described During first average speed in specific speed section, first speed restrictive block and the second speed limit in the monitoring section are obtained Section, and it is the specific speed section to take the common factor of first speed restrictive block and second speed restrictive block；For By each vehicle in the monitoring section in first period, when the first average speed of the vehicle is positioned at described specific During speed interval, then retain the first average speed of the vehicle；When the first average speed of the vehicle is not located at the spy When determining speed interval, then the first average speed of the vehicle is deleted；Wherein, first speed restrictive block is specifically from VminArrive Vmax, second speed restrictive block is specifically from 0.6VmaxTo Vmax, the VminIt is the minimum speed limit in the monitoring section, it is described VmaxIt is the maximum speed limit in the monitoring section.
The computing module 13, specifically for calculating described the using the first average speed positioned at specific speed section During the second average speed of one period, by the specific speed interval division into k speed subranges, for positioned at specific Each first average speed of speed interval finds corresponding speed subranges, and it is flat to count corresponding to each speed subranges first Equal number of speed amount, and obtain corresponding relation of each speed subranges with corresponding first average speed quantity；For each speed Subinterval is spent, the corresponding relation using the speed subranges with corresponding first average speed quantity, is the speed sub-district Between distribute weight parameter, and using all first average speeds corresponding to the speed subranges, calculate the speed subranges Corresponding 4th average speed；Utilize weight parameter corresponding to each speed subranges difference in the k speed subranges And the 4th average speed, calculate the second average speed of first period.
For each speed subranges in the k speed subranges, the computing module 13, specifically for utilizing The speed subranges and the corresponding relation of corresponding first average speed quantity, weight parameter is distributed for the speed subranges During, according to the order from low speed subinterval to high speed subinterval, the k speed subranges are ranked up；It is determined that First sub- weight parameter q1 of i-th of speed subranges is (2*i)/[(1+k) * k], and first according to corresponding to speed subranges Average speed quantity, the second sub- weight parameter q2 for determining i-th of speed subranges areI's takes It is worth for 1,2 ..., k, niFor the first average speed quantity, n corresponding to i-th of speed subrangesjIt is corresponding for j-th of speed subranges The first average speed quantity；The first sub- weight parameter in high speed subinterval is more than the first sub- weight parameter in low speed subinterval, The second small sub- weight parameter of first average speed quantity is more than the second big sub- weight parameter of the first average speed quantity；Calculate Weight ratio λ corresponding to first sub- weight parameter of all speed subranges1And the second sub- weight of all speed subranges Weight ratio λ corresponding to parameter2, and the weight parameter for calculating i-th of speed subranges is specially：(i-th of speed sub-district Between the first sub- weight parameter * described in weight ratio λ1Weight described in the second sub- weight parameter * of i-th of speed subranges of)+( Ratio λ2)。
The computing module 13, specifically for using N number of first period respectively corresponding to the second average speed, calculate the During 3rd average speed corresponding to two periods, the 3rd average speed corresponding to calculating second period isThe value of the i is 1,2 ..., N, the niIt is first flat for what is filtered out corresponding to i-th of first periods Equal number of speed amount, the n is all the first average speed quantity filtered out, the V corresponding to N number of first periodiFor i-th Second average speed corresponding to first period；The computing module 13, specifically for flat using the corresponding to the second period the 3rd During equal speed calculates free stream velocity, using the 3rd average speed corresponding to second period as free stream velocity； Or calculate free stream velocity using the 3rd average speed corresponding to the second period of continuous N；When using continuous N second During the 3rd average speed calculates free stream velocity corresponding to section, calculating free stream velocity isInstitute The value for stating j is 1,2 ..., M, the mjFor the first average speed quantity filtered out corresponding to j-th of second periods, the m For all the first average speed quantity filtered out, the V corresponding to M the second periodsjFor corresponding to j-th of second periods Three average speeds.
Wherein, the modules of apparatus of the present invention can be integrated in one, and can also be deployed separately.Above-mentioned module can close And be a module, multiple submodule can also be further split into.
Through the above description of the embodiments, those skilled in the art can be understood that the present invention can be by Software adds the mode of required general hardware platform to realize, naturally it is also possible to which by hardware, but the former is more in many cases Good embodiment.Based on such understanding, what technical scheme substantially contributed to prior art in other words Part can be embodied in the form of software product, and the computer software product is stored in a storage medium, if including It is dry to instruct to cause a computer equipment (be personal computer, server, or network equipment etc.) to perform this hair Method described in bright each embodiment.It will be appreciated by those skilled in the art that accompanying drawing is the schematic diagram of a preferred embodiment, Module or flow in accompanying drawing are not necessarily implemented necessary to the present invention.
It will be appreciated by those skilled in the art that the module in device in embodiment can describe be divided according to embodiment It is distributed in the device of embodiment, respective change can also be carried out and be disposed other than in one or more devices of the present embodiment.On The module for stating embodiment can be merged into a module, can also be further split into multiple submodule.The embodiments of the present invention Sequence number is for illustration only, does not represent the quality of embodiment.
Disclosed above is only several specific embodiments of the present invention, and still, the present invention is not limited to this, any ability What the technical staff in domain can think change should all fall into protection scope of the present invention.

Claims (8)

1. a kind of computational methods of free stream velocity, it is characterised in that for monitoring section, the first headend equipment is used to gather institute The car data of crossing of the porch in monitoring section is stated, car number is crossed in the exit that the second headend equipment is used to gather the monitoring section According to the described method comprises the following steps：
For each first period in continuous N number of first period, obtain first headend equipment and adopted in first period The second historical data that the first historical data and second headend equipment collected collects in first period, and utilize First historical data and second historical data, it is determined that by each of the monitoring section within first period First average speed of vehicle；First positioned at specific speed section is filtered out from the first average speed of each vehicle Average speed, and utilize the second average speed of the first average speed calculating first period positioned at specific speed section；
Using the second average speed corresponding to N number of first period difference, the 3rd average speed corresponding to the second period is calculated, And calculate free stream velocity using the 3rd average speed corresponding to second period；
Wherein, it is described using the second average speed corresponding to N number of first period difference, calculate the 3rd corresponding to the second period The process of average speed, is specifically included：3rd average speed corresponding to calculating second period isIts In, the value of the i is 1,2 ..., N, the niFor the first average speed quantity filtered out corresponding to i-th of first periods, The n is all the first average speed quantity filtered out, the V corresponding to N number of first periodiFor i-th of first periods pair The second average speed answered；
The process that free stream velocity is calculated using the 3rd average speed corresponding to the second period, is specifically included：Utilize continuous N 3rd average speed corresponding to individual second period calculates free stream velocity；It is average using the corresponding to the second period of continuous N the 3rd Speed calculates the process of free stream velocity, specifically includes：Calculating free stream velocity isWherein, the j Value is 1,2 ..., M, the mjFor the first average speed quantity filtered out corresponding to j-th of second periods, the m is M All the first average speed quantity filtered out, the V corresponding to second periodjIt is flat for the corresponding to j-th of second periods the 3rd Equal speed；
The process of the first average speed positioned at specific speed section is filtered out in first average speed from each vehicle, Specifically include：Obtain it is described monitoring section the first speed restrictive block and the second speed restrictive block, and take first speed restrictive block and The common factor of second speed restrictive block is the specific speed section；For passing through the monitoring section within first period Each vehicle, when the first average speed of the vehicle is located at the specific speed section, retain the first of the vehicle Average speed；When the first average speed of the vehicle is not located at the specific speed section, the first of the vehicle is deleted Average speed；Wherein, first speed restrictive block is from VminTo Vmax, second speed restrictive block is from 0.6VmaxTo Vmax, VminBe it is described monitoring section minimum speed limit, VmaxIt is the maximum speed limit in the monitoring section.
2. according to the method for claim 1, it is characterised in that
It is described to utilize first historical data and second historical data, it is determined that passing through the prison within first period The process of the first average speed of each vehicle in section is controlled, is specifically included：For passing through the prison within first period Each vehicle in section is controlled, determines that the vehicle enters the monitoring section using the first historical data corresponding to the vehicle The very first time, and using the second historical data corresponding to the vehicle determine the vehicle leave it is described monitoring section second when Between；Running time of the vehicle in the monitoring section is determined using the very first time and second time, and is utilized First average speed of vehicle described in the length computation in the running time and the monitoring section.
3. according to the method for claim 1, it is characterised in that the first average speed using positioned at specific speed section Degree calculates the process of the second average speed of first period, specifically includes：
By the specific speed interval division into k speed subranges, for positioned at each first average speed in specific speed section Degree finds corresponding speed subranges, counts the first average speed quantity corresponding to each speed subranges, and obtain each speed Spend corresponding relation of the subinterval with corresponding first average speed quantity；
For each speed subranges, the corresponding relation using the speed subranges with corresponding first average speed quantity, Weight parameter is distributed for the speed subranges, and using all first average speeds corresponding to the speed subranges, is calculated 4th average speed corresponding to the speed subranges；
Utilize weight parameter and Siping City's average rate corresponding to each speed subranges difference in the k speed subranges Degree, calculate the second average speed of first period.
4. according to the method for claim 3, it is characterised in that for each speed in the k speed subranges Section, the corresponding relation using the speed subranges with corresponding first average speed quantity, it is the speed sub-district Between distribute weight parameter process, specifically include：
According to the order from low speed subinterval to high speed subinterval, the k speed subranges are ranked up；
The the first sub- weight parameter q1 for determining i-th of speed subranges is (2*i)/[(1+k) * k], and according to speed subranges pair The the first average speed quantity answered, the second sub- weight parameter q2 for determining i-th of speed subranges are Wherein, i value is 1,2 ..., k, xiFor the first average speed quantity, x corresponding to i-th of speed subrangesjFor j-th of speed First average speed quantity corresponding to subinterval；The first sub- weight parameter in high speed subinterval is more than first son in low speed subinterval Weight parameter, the second small sub- weight parameter of the first average speed quantity are more than the second big sub- weight of the first average speed quantity Parameter；
Calculate weight ratio λ corresponding to the first sub- weight parameter of all speed subranges1And the second of all speed subranges Weight ratio λ corresponding to sub- weight parameter2, and the weight parameter for calculating i-th of speed subranges is specially：(i-th of speed Spend weight ratio λ described in the first sub- weight parameter * in subinterval1The second sub- weight parameter * institutes of i-th of speed subranges of)+( State weight ratio λ2)。
5. a kind of computing device of free stream velocity, it is characterised in that for monitoring section, the first headend equipment is used to gather institute The car data of crossing of the porch in monitoring section is stated, car number is crossed in the exit that the second headend equipment is used to gather the monitoring section According to the computing device of the free stream velocity specifically includes：
Determining module, for for each first period in continuous N number of first period, obtaining first headend equipment in institute State the first historical data that the first period collected and second that second headend equipment collects in first period is gone through History data, using first historical data and second historical data, it is determined that passing through the prison within first period Control the first average speed of each vehicle in section；
Screening module, for the first average speed of each vehicle determined for the determining module, from each vehicle The first average speed in filter out the first average speed positioned at specific speed section；
Computing module, for the first average speed positioned at specific speed section filtered out for screening module, using positioned at First average speed in specific speed section calculates the second average speed of first period；And utilize described N number of first Second average speed corresponding to period difference, the 3rd average speed corresponding to the second period is calculated, and utilize second period Corresponding 3rd average speed calculates free stream velocity；
Wherein, the computing module, specifically for using N number of first period respectively corresponding to the second average speed, calculate the During 3rd average speed corresponding to two periods, the 3rd average speed corresponding to calculating second period isThe value of the i is 1,2 ..., N, the niIt is first flat for what is filtered out corresponding to i-th of first periods Equal number of speed amount, the n is all the first average speed quantity filtered out, the V corresponding to N number of first periodiFor i-th Second average speed corresponding to first period；
The computing module, specifically for calculating the process of free stream velocity using the 3rd average speed corresponding to the second period In, calculate free stream velocity using the 3rd average speed corresponding to the second period of continuous N；Utilizing the second period of continuous N During corresponding 3rd average speed calculates free stream velocity, calculating free stream velocity isThe j Value be 1,2 ..., M, the mjFor the first average speed quantity filtered out corresponding to j-th of second periods, the m is M All the first average speed quantity filtered out, the V corresponding to individual second periodjFor the 3rd corresponding to j-th of second periods Average speed；
The screening module, specifically for being filtered out in the first average speed from each vehicle positioned at the specific speed During the first average speed for spending section, first speed restrictive block and the second speed restrictive block in the monitoring section are obtained, And it is the specific speed section to take the common factor of first speed restrictive block and second speed restrictive block；For described By each vehicle in the monitoring section in one period, when the first average speed of the vehicle is located at the specific speed area Between when, then retain the first average speed of the vehicle；When the first average speed of the vehicle is not located at the specific speed During section, then the first average speed of the vehicle is deleted；Wherein, first speed restrictive block is specifically from VminTo Vmax, institute It is specifically from 0.6V to state the second speed restrictive blockmaxTo Vmax, the VminBe it is described monitoring section minimum speed limit, the VmaxIt is institute State the maximum speed limit in monitoring section.
6. device according to claim 5, it is characterised in that
The determining module, specifically for utilizing first historical data and second historical data, it is determined that described During the first average speed for passing through each vehicle in the monitoring section in first period, in first period Interior each vehicle by the monitoring section, determine that the vehicle enters institute using the first historical data corresponding to the vehicle The very first time in monitoring section is stated, and determines that the vehicle leaves the monitoring using the second historical data corresponding to the vehicle Second time in section；Traveling of the vehicle in the monitoring section is determined using the very first time and second time Time, and utilize the first average speed of vehicle described in the length computation in the running time and the monitoring section.
7. device according to claim 5, it is characterised in that
The computing module, specifically for calculating first period using the first average speed positioned at specific speed section The second average speed during, by the specific speed interval division into k speed subranges, for positioned at specific speed area Between each first average speed find corresponding speed subranges, count the first average speed corresponding to each speed subranges Quantity, and obtain corresponding relation of each speed subranges with corresponding first average speed quantity；For each speed sub-district Between, the corresponding relation using the speed subranges with corresponding first average speed quantity, distributed for the speed subranges Weight parameter, and using all first average speeds corresponding to the speed subranges, calculate corresponding to the speed subranges 4th average speed；Using each speed subranges in the k speed subranges respectively corresponding to weight parameter and the Four average speeds, calculate the second average speed of first period.
8. device according to claim 7, it is characterised in that for each speed in the k speed subranges Section, the computing module, specifically for corresponding with corresponding first average speed quantity using the speed subranges Relation, during distributing weight parameter for the speed subranges, according to the order from low speed subinterval to high speed subinterval, The k speed subranges are ranked up；
The the first sub- weight parameter q1 for determining i-th of speed subranges is (2*i)/[(1+k) * k], and according to speed subranges pair The the first average speed quantity answered, the second sub- weight parameter q2 for determining i-th of speed subranges are Wherein, i value is 1,2 ..., k, xiFor the first average speed quantity, x corresponding to i-th of speed subrangesjFor j-th of speed First average speed quantity corresponding to subinterval；The first sub- weight parameter in high speed subinterval is more than first son in low speed subinterval Weight parameter, the second small sub- weight parameter of the first average speed quantity are more than the second big sub- weight of the first average speed quantity Parameter；
Calculate weight ratio λ corresponding to the first sub- weight parameter of all speed subranges1And the second of all speed subranges Weight ratio λ corresponding to sub- weight parameter2, and the weight parameter for calculating i-th of speed subranges is specially：(i-th of speed Spend weight ratio λ described in the first sub- weight parameter * in subinterval1The second sub- weight parameter * institutes of i-th of speed subranges of)+( State weight ratio λ2)。
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